Introduce a new icon particle. It follows the icon
spec (https://specifications.freedesktop.org/icon-theme-spec/latest/index.html).
Rendering logic is taken from fuzzel (using nanosvg + libpng), while loading
logic is taken from sway. Standard usage is with `use-tag = false` which expands
the provided string template and then loads the string as the icon name. There
are settings to manually override the base paths, themes, etc. The second usage
which is required for tray support is a special icon tag that transfers raw
pixmaps. With `use-tag = true` it first expands the string, and then uses that
output to find an icon pixmap tag. To reduce memory usage, themes are reference
counted so they can be passed down the configuration stack without having to
load them in multiple times.
For programmability, a fallback particle can be specified if no icon/tag is
found `fallback: ...`. And the new icon pixmap tag can be existence checked in
map conditions using `+{tag_name}`.
Future work to be done in follow up diffs:
1. Icon caching. Currently performs an icon lookup on each instantiation & a
render on each refresh.
2. Theme caching. Changing theme directories results in a new "theme collection"
being created resulting in the possibility of duplicated theme loading.
This allows you to configure the width of each side of the border
individually. border.width can still be used, and will set all four
borders to the same width.
Closes#77
This is an integer that specifies the amount of scrolling that needs
to be accumulated before a wheel-up/down event is emitted.
A higher value means you need to drag your fingers a longer distance
before the event is emitted.
The default is 30.
This allows the backend to support multi-seat "properly", by checking
against the correct seat. Before this, when we used a single, global
xcursor value, a seat whose pointer needed to be updated would not be
updated.
This is trivial in the Wayland backend; just instantiate a pixman
pointing to the same mmapped memory as the wayland buffer.
In the XCB backend, we change the implementation slightly; instead of
rendering via a cairo XCB surface backend (to a server side pixmap),
which is then blitted to the window in commit(), we now render to a
client-side pixman pixmap, and blit it using xcb_put_image() in
commit().
All decoration, particle and module interfaces now takes a
pixman_image_t parameter, and all drawing is done using pixman APIs.
The wayland/xcb backends implement a new interface functions,
get_pixman_image(), that should return a pixman image instance that is
suitable for rendering.
In the wayland backend, the image uses the same backing data as the
cairo surface.
In the XCB backend, we create a new image each time, and then blit it
to the cairo surface at commit time.
